PIN photodetector

Abstract

A PIN photodetector includes an n-type semiconductor layer, an n-type semiconductor cap layer, a first plurality of p-type regions located within the n-type semiconductor cap layer and separated from one another by a distance d1, and an absorber layer located between the n-type semiconductor layer and the n-type semiconductor cap layer including the first plurality of p-type regions. The plurality of p-type regions are electrically connected to one another to provide an electrical response to light incident to the PIN photodetector.

The invention claimed is: 
     
       1. A PIN photodetector comprising:
 a first semiconductor layer; 
 a second semiconductor cap layer; 
 an array of semiconductor regions located within the second semiconductor cap layer, wherein each of the semiconductor regions in the array are separated from one another by approximately the same distance d 1 ; 
 an absorber layer located between the first semiconductor layer and the second semiconductor cap layer including the of semiconductor regions; and 
 wherein one or more electrical responses are generated by the array of semiconductor regions in response to light incident to the PIN photodetector. 
 
     
     
       2. The PIN photodetector of  claim 1 , wherein the array of semiconductor regions is a two-dimensional array. 
     
     
       3. The PIN photodetector of  claim 1 , wherein the first semiconductor layer is an n-type semiconductor layer, the second semiconductor cap layer is an n-type semiconductor cap layer, and the array of semiconductor regions are p-type regions. 
     
     
       4. The PIN photodetector of  claim 1 , wherein the first semiconductor layer, the second semiconductor cap layer, the array of semiconductor regions, and the absorber layer are located on a first semiconductor die. 
     
     
       5. The PIN photodetector of  claim 4 , wherein connections between the array of semiconductor regions are fabricated as part of the first semiconductor die. 
     
     
       6. The PIN photodetector of  claim 4 , further including an electrical contact formed on each of the semiconductor regions included in the array of semiconductor regions. 
     
     
       7. The PIN photodetector of  claim 6 , further including conductors located on each of the electrical contacts. 
     
     
       8. The PIN photodetector of  claim 7 , further including a conductive layer connected to the array of semiconductor regions via the conductors and electrical contacts associated with each semiconductor region. 
     
     
       9. The PIN photodetector of  claim 8 , wherein the conductive layer is included as part of an off-die package. 
     
     
       10. The PIN photodetector of  claim 9 , wherein the off-die package is one of an integrated circuit package or a printed circuit board. 
     
     
       11. The PIN photodetector of  claim 1 , wherein the array of semiconductor regions generates a plurality of depletion regions within the absorber layer separated by undepleted regions within the absorber layer. 
     
     
       12. The PIN photodetector of  claim 11 , wherein adjacent depletion regions are separated by a distance d 3 , wherein the distance d 3  is approximately equal to or less than a diffusion length associated with charge carriers in the absorber layer. 
     
     
       13. The PIN photodetector of  claim 1 , further including a guard ring located on a same plane as the array of semiconductor regions, wherein the guard ring surrounds the array of semiconductor regions. 
     
     
       14. An optical detection system comprising:
 a PIN photodetector comprising:
 an n-type semiconductor layer; 
 an n-type semiconductor cap layer; 
 a plurality of p-type diffusion regions diffused within the n-type semiconductor cap layer and separated from one another by a distance d 1 , the plurality of p-type diffusion regions arranged in a two-dimensional array of p-type diffusion regions; 
 an absorber layer located between the n-type semiconductor layer and the n-type semiconductor cap layer, wherein the plurality of p-type diffusion regions generate a plurality of depletion regions within the absorber layer, wherein each of the depletion regions are separated from adjacent depletion regions by a distance d 3 ; and 
 
 a signal conditioning circuit connected to receive an electrical response generated by the PIN photodetector, wherein the signal conditioning circuit is characterized by a bandwidth. 
 
     
     
       15. The optical detection system of  claim 14 , wherein the distance d 3  between adjacent depletion regions is selected based on the bandwidth of the signal conditioning circuit and wherein the distance d 3  is selected such that a transit time of charge carriers created between the depletion regions is less than 1/bandwidth of the signal conditioning circuit. 
     
     
       16. The optical detection system of  claim 14 , wherein the PIN photodetector further includes a plurality of conductors in electrical contact with the plurality of p-type diffusion regions to provide the electrical response to charge carriers collected by the plurality of p-type diffusion regions. 
     
     
       17. The optical detection system of  claim 14 , wherein an electrical connection to the plurality of p-type diffusion regions is made within a packaging or carrier associated with the PIN photodetector. 
     
     
       18. The optical detection system of  claim 14 , wherein the PIN photodetector further comprises:
 a plurality of electrical contacts, each electrical contact associated with one of the p-type diffusion regions; and 
 a plurality of conductors, each conductor associated with one of the plurality of electrical contacts. 
 
     
     
       19. The optical detection system of  claim 18 , further comprising:
 one or more conductive layers connected to the array of p-type diffusion regions via the conductors and electrical contacts associated with each p-type diffusion region, wherein the one or more conductive layers is included as part of an off-die package contacting the PIN photodetector.